FiiO K1 portable Headphone Amplifier and DAC. The thumb-sized K1 from FiiO is a portable headphone amplifier and DAC with mastering quality sound that supports resolutions of up to 24-bit/ 96 kHz. The unit offers true plug-and-play operation with no batteries to charge and no drivers required for operation. The K1's audio architecture utilises Savitechs's SA9023A USB receiver to decode USB audio, while the high fidelity, low noise TI PCM5102 DAC chip outputs to the TPA 61332A headphone amplifier, which is capable of driving most headphones with a range of 16 to 100 ohms. So buy this Fiio K1 portable Headphone Amplifier and DAC - Plug and Play Now £35.99.